Aqueous heat pump methods and systems

ABSTRACT

Devices, methods, systems, and computer-readable media for an aqueous carbon dioxide (CO 2 ) heat pump are described herein. One or more embodiments include a system comprising a compressor to lower a first CO 2  pressure of a first chamber and increase a second CO 2  pressure of a second chamber, a liquid pump to remove a liquid from the first chamber and provide liquid to the second chamber, wherein the liquid is a CO 2  aqueous solution, and a heat exchanger to alter a temperature of the liquid when the liquid is removed from the first chamber and provided to the second chamber.

TECHNICAL FIELD

The present disclosure relates to methods, devices, and systems, for anaqueous heat pump.

BACKGROUND

Heat pumps based on vapor compression can suffer efficiency degradationfrom a theoretical maximum due to a number of practical limitations,such as a lack of environmentally inert refrigerants with desirablethermodynamic properties. The desirable thermodynamic properties caninclude a relatively high value of enthalpy of vaporization and/oradequate vapor pressure. In addition, there can also be degradationfactors due to mechanical and heat transfer inefficiencies.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an example of a system for an aqueous heat pump according toone or more embodiments of the present disclosure.

FIG. 2 is an example of a system for an aqueous heat pump with furtherimprovement in efficiency according to one or more embodiments of thepresent disclosure.

DETAILED DESCRIPTION

Devices, methods, and systems for an aqueous heat pump are describedherein. For example, one or more embodiments can include a systemcomprising a compressor to lower a first pressure of a first chamber andincrease a second pressure of a second chamber, a liquid pump to removea liquid from the first chamber and provide the liquid to the secondchamber (e.g., recalculate liquid between the first chamber and thesecond chamber), wherein the liquid is capable of absorbing anddesorbing a gas (e.g., CO₂, etc.), and a heat exchanger to alter atemperature of the liquid when the liquid is removed from the firstchamber and provided to the second chamber. In some examples, the heatexchanger can be utilized to remove heat from the liquid leaving thesecond chamber and a counter-flow heat exchanger can be utilized toallow heat exchanges between the liquid leaving the second chamber andliquid entering the second chamber.

The thermodynamic cycle of the aqueous heat pump can be based on aphysical-chemical interaction between gas and an aqueous solution. Forexample, the aqueous heat pump can be based in part on an endothermicdesorption of carbon dioxide in a depressurization chamber and anexothermic absorption of carbon dioxide in a pressurization chamber. Thepressure difference between a depressurization chamber (e.g., desorptionchamber) and a pressurized chamber (e.g., absorption chamber) can bemaintained using a compressor (e.g., gaseous compressor, carbon dioxidecompressor).

The aqueous heat pump can utilize a liquid pump to keep liquid (e.g.,aqueous carbon dioxide solution) at a sufficient rate of liquidrecirculation between the depressurization chamber and thepressurization chamber. In some embodiments, the sufficient rate ofliquid recirculation can be needed to maintain a relatively constant CO₂concentration in the aqueous solution throughout the system. Theseembodiments can prevent CO₂ depletion in the aqueous solution within thefirst chamber. The liquid pump can be located at a number of differentlocations between the depressurization chamber and the pressurizationchamber. In some embodiments, a recuperation heat exchanger can beutilized to prevent thermal “leak back”. For example, the recuperationheat exchanger can be utilized to prevent cooler liquid from thedepressurization chamber from being provided to the pressurizationchamber and to prevent warmer liquid from the pressurization chamberfrom being provided to the depressurization chamber.

The liquid provided to the depressurization chamber and thepressurization chamber can be provided by a liquid dispersion system.The liquid dispersion system can create a mist and/or spray of theliquid to increase a surface area of the liquid that is provided to thedepressurization chamber and the pressurization chamber. The liquiddispersion system can increase (e.g., accelerate) the rate limitingprocess of carbon dioxide absorption and/or desorption by increasing thesurface area of the provided liquid. Increasing the surface area of theprovided liquid can increase an interaction between the aqueous carbondioxide solution and the gaseous carbon dioxide within thedepressurization chamber and the pressurization chamber.

In the following detailed description, reference is made to theaccompanying drawings that form a part hereof. The drawings show by wayof illustration how one or more embodiments of the disclosure may bepracticed.

These embodiments are described in sufficient detail to enable those ofordinary skill in the art to practice one or more embodiments of thisdisclosure. It is to be understood that other embodiments may beutilized and that process changes may be made without departing from thescope of the present disclosure.

As will be appreciated, elements shown in the various embodiments hereincan be added, exchanged, combined, and/or eliminated so as to provide anumber of additional embodiments of the present disclosure. Theproportion and the relative scale of the elements provided in thefigures are intended to illustrate the embodiments of the presentdisclosure, and should not be taken in a limiting sense.

The figures herein follow a numbering convention in which the firstdigit or digits correspond to the drawing figure number and theremaining digits identify an element or component in the drawing.Similar elements or components between different figures may beidentified by the use of similar digits.

As used herein, “a” or “a number of” something can refer to one or moresuch things. For example, “a number of widgets” can refer to one or morewidgets. Additionally, the designator “N”, as used herein, particularlywith respect to reference numerals in the drawings, indicates that anumber of the particular feature so designated can be included with anumber of embodiments of the present disclosure.

FIG. 1 is an example of a system 100 for an aqueous heat pump accordingto one or more embodiments of the present disclosure. The system 100 canutilize a physical-chemical interaction between gaseous carbon dioxideand a liquid (e.g., liquid aqueous solution, aqueous carbon dioxidesolution, heterogeneous refrigerant comprising carbon dioxide, etc.).The system 100 can provide a cooling heat exchanger 112-1 (e.g., heatexchanger that absorbs heat from ambient, etc.) and a warming heatexchanger 112-2 (e.g., heat exchanger that rejects heat to the ambient,etc.).

The system 100 can include a first chamber 102 (e.g., desorptionchamber, depressurization chamber, etc.) that is coupled to a secondchamber 104 (e.g., absorption chamber, pressurization chamber, etc.) bya compressor 106 (e.g., carbon dioxide compressor, etc.). The compressor106 can remove gaseous carbon dioxide from the first chamber 102 tolower a pressure within the first chamber 102. In some embodiments, thecompressor 106 can lower the pressure of the first chamber 102 toapproximately 3 BAR (e.g., 2 BAR-4 BAR, etc.). The compressor 106 canutilize the gaseous carbon dioxide removed from the first chamber 102 toincrease a pressure of the second chamber 104. In some embodiments, thecompressor 106 can increase the pressure of the second chamber 104 toapproximately 8 BAR (e.g., 7 BAR-9 BAR, etc.).

The difference in pressure between the first chamber 102 and the secondchamber 104 can move the liquid from the second chamber 104 to the firstchamber 102 via a number of coupled liquid lines 116, 118. For example,liquid 124-2 can accumulate at a bottom portion of the second chamber104. In this example, the difference in pressure between the firstchamber 102 and the second chamber 104 can move the liquid 124-2 througha heat exchanger 112-2, through a counter-flow energy recover heatexchanger 110, and to a dispersion unit 114-1 of the first chamber 102.The liquid flow from the first chamber 102 to the second chamber 104through lines 116 and 122 can be driven by liquid pump 108-1 to overcomethe pressure difference between the two chambers.

As described herein, the process of carbon dioxide desorption and/orabsorption within the first chamber 102 and the second chamber 104respectively can be a rate limiting step within the system 100. Theabsorption and/or desorption rate of carbon dioxide or other gas that iscapable of absorption and desorption as described herein can beincreased within the system 100 by increasing the surface area of theprovided liquid via the liquid dispersion units 114-1, 114-2. The liquiddispersion units 114-1, 114-2 can increase the surface area of theprovided liquid by creating a plurality of droplets 126-1, 126-2 fromthe provided liquid. For example, the liquid dispersion units 114-1,114-2 can create a mist with the provided liquid so that a plurality ofdroplets 126-1, 126-2 of the provided liquid can interact with thegaseous carbon dioxide.

In some embodiments, the first chamber 102 can be a desorption chamberthat is utilized to desorb carbon dioxide from the plurality of droplets126-1 into the first chamber 102 (e.g., decreasing a concentration ofcarbon dioxide in the plurality of droplets 126-1, etc.). Desorbing thecarbon dioxide from the plurality of droplets 126-1 can produce anendothermic reaction and cool the droplets 126-1 and liquid 124-1 withinthe first chamber 102. In some embodiments, the first chamber 102 andother components between the first chamber 102 and counter-flow heatexchanger 110 (e.g., liquid lines 116, 118, liquid dispersion unit114-1, liquid pump 108, etc.) can be referred to as a “cold side”. Thatis, the first chamber 102 and other components of the “cold side” canmaintain a temperature of the liquid that is relatively colder than the“warm side” (e.g., second chamber 104 and components betweencounter-flow heat exchanger 110 and the second chamber 104). In someembodiments, the “cold side” can maintain a temperature lower than 10degrees C.

In some embodiments, the second chamber 104 can be an absorption chamberthat is utilized to absorb carbon dioxide from the second chamber 104into the plurality of droplets 126-2 (e.g., increasing a concentrationof carbon dioxide in the plurality of droplets 126-2). Absorbing thecarbon dioxide into the plurality of droplets 126-1 can produce anexothermic reaction and warm the droplets 126-2 and liquid 124-2 withinthe second chamber 104. The second chamber 104 and other componentsbetween the second chamber 104 and counter-flow heat exchanger 110 canbe referred to as a “warm side”. That is, the second chamber 104 andother components of the “warm side” can maintain a temperature of theliquid that is relatively warmer than the “cold side”. In someembodiments, the “warm side” can maintain a temperature higher than 35degrees C. As described herein, an efficiency degradation factor caninclude thermal “leak back” from liquid solution recirculation (e.g.,pumping warm liquid to a “cold side” and/or pumping cool liquid to the“warm side, etc.).

The thermal “leak back” from liquid solution recirculation can bereduced by coupling a counter-flow energy recovery heat exchanger 110between the first chamber 102 and the second chamber 104. Thecounter-flow energy recovery heat exchanger 110 can utilize cool liquidfrom the “cold side” to cool liquid from the “warm side” and vice versa.For example, liquid from the first chamber 102 can enter thecounter-flow energy recovery heat exchanger 110 and cool liquid from thesecond chamber 104 entering the counter-flow energy recovery heatexchanger 110. In this example, liquid from the second chamber 104 canenter the counter-flow energy recovery heat exchanger 110 and warmliquid from the first chamber 102.

The counter-flow energy recovery heat exchanger 110 can be utilized towarm liquid from the first chamber 102 before the liquid is provided tothe second chamber 104. For example, liquid from the first chamber 102can be approximately 10 degrees C. when entering the counter-flow energyrecovery heat exchanger 110. In this example, liquid from the secondchamber 104 can be approximately 35 degrees C. and utilized to warm theliquid from the first chamber 102. In this example, the liquid from thesecond chamber 104 can warm the liquid from the first chamber 102 toapproximately 35 degrees C. prior to being provided to the secondchamber 104. Thus, the counter-flow energy recovery heat exchanger 110can be utilized to ensure that liquid being provided to the firstchamber 102 is approximately 10 degrees C. and that liquid beingprovided to the second chamber is approximately 35 degrees C. The system100 can be utilized to provide a cooling heat exchanger 112-1 and awarming heat exchanger 112-2 that can provide cooling and/or heatingresources to a building.

FIG. 2 is an example of a system 200 for an aqueous heat pump accordingto one or more embodiments of the present disclosure. The system 200 canoperate in the same and/or similar manner as system 100 as referenced inFIG. 1, but can be utilized to reduce a power consumption of the liquidpump 208-1 by utilizing a liquid motor 208-2 to recuperate the hydraulicpower from the liquid flowing from chamber 204 to chamber 202. Thesystem 200 can include similar features, including, but not limited to:a first chamber 202, a second chamber 204, a number of heat exchangers(e.g., cooling heat exchanger 212-1, warming heat exchanger 212-2,etc.), a counter-flow recovery heat exchanger 210, a liquid pump 208-1,a compressor 206, and a number lines 222, 220, 218, 216.

In some embodiments, the liquid pump 208-1 can be utilized to control arate of liquid circulation within the system 200. In addition to theliquid pump 208-1, a recuperation motor 208-2 (e.g., recuperation pump,etc.) can be utilized to control a rate of liquid circulation within thesystem 200. For example, the liquid pump 208-1 can pump liquid from thefirst chamber 202 through the counter-flow energy recovery heatexchanger 210 to provide the liquid to the second chamber 204. In thisexample, the recuperation motor 208-2 can pump liquid received throughthe counter-flow energy recovery heat exchanger 210 from the secondchamber 204 and provide the liquid to the first chamber 202.

In some embodiments, the recuperation motor can generate power from theliquid flow from the second chamber 204 to the first chamber 202. Forexample, the liquid pump 208-1 can be mechanically linked with theenergy recuperation motor 208-1 through a common shaft wherein therecuperated power from motor 208-2 is fed to pump 208-1. Thus, in thisexample can reduce the power consumption of pump 208-1 to conserve powerand improve efficiency of the system 200.

Although specific embodiments have been illustrated and describedherein, those of ordinary skill in the art will appreciate that anyarrangement calculated to achieve the same techniques can be substitutedfor the specific embodiments shown. This disclosure is intended to coverany and all adaptations or variations of various embodiments of thedisclosure.

It is to be understood that the above description has been made in anillustrative fashion, and not a restrictive one. Combination of theabove embodiments, and other embodiments not specifically describedherein will be apparent to those of skill in the art upon reviewing theabove description.

The scope of the various embodiments of the disclosure includes anyother applications in which the above structures and methods are used.Therefore, the scope of various embodiments of the disclosure should bedetermined with reference to the appended claims, along with the fullrange of equivalents to which such claims are entitled.

In the foregoing Detailed Description, various features are groupedtogether in example embodiments illustrated in the figures for thepurpose of streamlining the disclosure. This method of disclosure is notto be interpreted as reflecting an intention that the embodiments of thedisclosure require more features than are expressly recited in eachclaim.

Rather, as the following claims reflect, inventive subject matter liesin less than all features of a single disclosed embodiment. Thus, thefollowing claims are hereby incorporated into the Detailed Description,with each claim standing on its own as a separate embodiment.

What is claimed:
 1. 1 A system for an aqueous heat pump, comprising: acompressor to lower a first pressure of a first chamber and increase asecond pressure of a second chamber; a liquid pump to remove a liquidfrom the first chamber and provide liquid to the second chamber, whereinthe liquid is capable of absorbing and desorbing a gas; and a heatexchanger to alter a temperature of the liquid when the liquid isremoved from the first chamber and provided to the second chamber. 2.The system of claim 1, wherein the liquid from the second chamber isremoved by the increased second pressure and provided to the firstchamber.
 3. The system of claim 2, wherein the heat exchanger alters atemperature of the liquid when the liquid is removed from the secondchamber and provided to the first chamber.
 4. The system of claim 1,wherein the heat exchanger is a counter-flow energy recovery heatexchanger.
 5. The system of claim 1, wherein the first pressure is lessthan half of the second pressure.
 6. The system of claim 1, comprising arecuperation motor to generate power from liquid flow from the secondchamber to the first chamber.
 7. The system of claim 6, wherein theliquid pump and the recuperation motor are mechanically linked.
 8. Asystem for an aqueous carbon dioxide (CO₂) heat pump, comprising: afirst chamber comprising a first CO₂ pressure and a second chambercomprising a second CO₂ pressure; a liquid pump to remove a liquid fromthe first chamber and provide liquid to the second chamber, wherein theliquid is able to reversibly absorb and desorb CO₂; a recuperation motorto generate power from liquid flow from the second chamber to the firstchamber; and a counter-flow energy recovery heat exchanger coupled tothe liquid pump and the recuperation motor to alter a temperature of theliquid.
 9. The system of claim 8, wherein the first CO₂ pressure isapproximately 3 BAR and the second CO₂ pressure is approximately 8 BAR.10. The system of claim 8, wherein the first chamber is a desorptionchamber and the second chamber is an absorption chamber.
 11. The systemof claim 8, wherein the liquid is a heterogeneous refrigerant comprisingCO₂.
 12. The system of claim 8, comprising a first dispersion systemcoupled to the first chamber to increase a surface area of the liquidwhen entering the first chamber.
 13. The system of claim 12, comprisinga second dispersion system coupled to the second chamber to increase asurface area of the liquid when entering the second chamber.
 14. Thesystem of claim 8, comprising: a first heat exchanger coupled to thefirst chamber to receive the liquid and provide a cooling mechanism; anda second heat exchanger coupled to the second chamber to receive theliquid and provide a heating mechanism.
 15. A system for an aqueouscarbon dioxide (CO₂) heat pump, comprising: a compressor to lower apressure of a desorption chamber and increase pressure of an absorptionchamber; a liquid pump coupled to a liquid reservoir within thedesorption chamber and coupled to a dispersion system within theabsorption chamber; and a counter-flow energy recovery heat exchangercoupled to the liquid reservoir within the desorption chamber andcoupled to a liquid reservoir within the absorption chamber.
 16. Themethod of claim 15, wherein the liquid pump provides aqueous CO₂ fromthe liquid reservoir within the desorption chamber to the dispersionsystem within the absorption chamber.
 17. The method of claim 16,wherein the compressor provides a difference in pressure between thedesorption chamber and the absorption chamber to provide aqueous CO₂from the liquid reservoir within the absorption chamber to a dispersionsystem within the desorption chamber.
 18. The method of claim 15,comprising a recuperation motor mechanically coupled to the liquid pumpto provide aqueous CO₂ from the liquid reservoir within the desorptionchamber to a dispersion system within the absorption chamber.
 19. Themethod of claim 15, wherein the counter-flow energy recovery heatexchanger alters a temperature of the liquid from the liquid reservoirwithin the desorption chamber from approximately 10 degrees C. toapproximately 35 degrees C. prior to being provided to the dispersionsystem within the absorption chamber.
 20. The method of claim 19,wherein the counter-flow energy recovery heat exchanger alters atemperature of the liquid from the liquid reservoir within theabsorption chamber from approximately 35 degrees C. to approximately 10degrees C. prior to being provided to a dispersion system within thedesorption chamber.